Existing high density bit drivers omit optical couplers or power drivers, or alternatively, provide a small number of I/0 bits. Existing products do not use a modular approach to the I/0 function, and use a single monolithic printed circuit board on which all components are mounted.
Present day I/O bit driver circuit boards require large areas and are not of a small size required in the new equipment design. A number of driver circuit boards are required to provide the I/O capability of the present invention. Repair of presently existing board are difficult to repair, and may require down time for equipment during the board repair.